Mystery Flower

Another flower from my bouquet.  Can't find out what it is, I assume it is a variety of Platycodon or Balloon Flower, but have never seen one like this.  Mr Google has let me down because I don't think he has seen this variety before.  The individual flowers are so tiny less than half an inch across when fully open and are clustered on a single stem to form a ball about three inches across.  The buds are typical for the platycodon in being like a balloon or a little parcel. It is extremely pretty, but I hope one of you clever folks out there can identify it for me. 
My blip is of one stem with the little flowers in all stages of opening, from tight buds to almost fully open.
As the flowers are so small I am tagging it for Tiny Tuesday, with thanks to dbifulco for hosting this month.